Display screen or portion thereof with transitional graphical user interface



FIG. 1 is a front view of the first image in a sequence of a first embodiment of a display screen or portion thereof with transitional graphical user interface, showing our new design;

FIG. 2 is a front view of the second image thereof;

FIG. 3 is a front view of the third image thereof;

FIG. 4 is a front view of the fourth image thereof;

FIG. 5 is a front view of the fifth image thereof;

FIG. 6 is a front view of the first image in a sequence of a second embodiment of a display screen or portion thereof with transitional graphical user interface, showing our new design;

FIG. 7 is a front view of the second image thereof;

FIG. 8 is a front view of the third image thereof;

FIG. 9 is a front view of the fourth image thereof;

FIG. 10 is a front view of the fifth image thereof;

FIG. 11 is a front view of the first image in a sequence of a third embodiment of a display screen or portion thereof with transitional graphical user interface, showing our new design;

FIG. 12 is a front view of the second image thereof;

FIG. 13 is a front view of the third image thereof;

FIG. 14 is a front view of the fourth image thereof;

FIG. 15 is a front view of the fifth image thereof;

FIG. 16 is a front view of the first image in a sequence of a fourth embodiment of a display screen or portion thereof with transitional graphical user interface, showing our new design;

FIG. 17 is a front view of the second image thereof;

FIG. 18 is a front view of the third image thereof;

FIG. 19 is a front view of the fourth image thereof; and,

FIG. 20 is a front view of the fifth image thereof.

The appearance of the transitional graphical user interface sequentially transitions between the images shown in FIGS. 1-5, FIGS. 6-10, FIGS. 11-15, and FIGS. 16-20, respectively. The process or period in which one image transitions to another forms no part of the claimed design.

The outer perimeter illustrated by a pair of broken lines in FIGS. 1-20 illustrates a display screen or portion thereof and forms no part of the claimed design. The dot-dash broken lines in FIGS. 1-20 illustrate a boundary of the claimed design. The remaining dashed broken lines shown in FIGS. 1-20 illustrate portions of the transitional graphical user interface that form no part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof with transitional graphical user interface, as shown and described. 